drivers/remoteproc/da8xx_remoteproc.c

   1 /*
   2  * Remote processor machine-specific module for DA8XX
   3  *
   4  * Copyright (C) 2013 Texas Instruments, Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * version 2 as published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/bitops.h>
  12 #include <linux/clk.h>
  13 #include <linux/err.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/io.h>
  16 #include <linux/irq.h>
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/remoteproc.h>
  21
  22 #include <mach/clock.h>   /* for davinci_clk_reset_assert/deassert() */
  23
  24 #include "remoteproc_internal.h"
  25
  26 static char *da8xx_fw_name;
  27 module_param(da8xx_fw_name, charp, S_IRUGO);
  28 MODULE_PARM_DESC(da8xx_fw_name,
  29                  "\n\t\tName of DSP firmware file in /lib/firmware"
  30                  " (if not specified defaults to 'rproc-dsp-fw')");
  31
  32 /*
  33  * OMAP-L138 Technical References:
  34  * http://www.ti.com/product/omap-l138
  35  */
  36 #define SYSCFG_CHIPSIG0 BIT(0)
  37 #define SYSCFG_CHIPSIG1 BIT(1)
  38 #define SYSCFG_CHIPSIG2 BIT(2)
  39 #define SYSCFG_CHIPSIG3 BIT(3)
  40 #define SYSCFG_CHIPSIG4 BIT(4)
  41
  42 /**
  43  * struct da8xx_rproc - da8xx remote processor instance state
  44  * @rproc: rproc handle
  45  * @dsp_clk: placeholder for platform's DSP clk
  46  * @ack_fxn: chip-specific ack function for ack'ing irq
  47  * @irq_data: ack_fxn function parameter
  48  * @chipsig: virt ptr to DSP interrupt registers (CHIPSIG & CHIPSIG_CLR)
  49  * @bootreg: virt ptr to DSP boot address register (HOST1CFG)
  50  * @irq: irq # used by this instance
  51  */
  52 struct da8xx_rproc {
  53         struct rproc *rproc;
  54         struct clk *dsp_clk;
  55         void (*ack_fxn)(struct irq_data *data);
  56         struct irq_data *irq_data;
  57         void __iomem *chipsig;
  58         void __iomem *bootreg;
  59         int irq;
  60 };
  61
  62 /**
  63  * handle_event() - inbound virtqueue message workqueue function
  64  *
  65  * This function is registered as a kernel thread and is scheduled by the
  66  * kernel handler.
  67  */
  68 static irqreturn_t handle_event(int irq, void *p)
  69 {
  70         struct rproc *rproc = (struct rproc *)p;
  71
  72         /* Process incoming buffers on all our vrings */
  73         rproc_vq_interrupt(rproc, 0);
  74         rproc_vq_interrupt(rproc, 1);
  75
  76         return IRQ_HANDLED;
  77 }
  78
  79 /**
  80  * da8xx_rproc_callback() - inbound virtqueue message handler
  81  *
  82  * This handler is invoked directly by the kernel whenever the remote
  83  * core (DSP) has modified the state of a virtqueue.  There is no
  84  * "payload" message indicating the virtqueue index as is the case with
  85  * mailbox-based implementations on OMAP4.  As such, this handler "polls"
  86  * each known virtqueue index for every invocation.
  87  */
  88 static irqreturn_t da8xx_rproc_callback(int irq, void *p)
  89 {
  90         struct rproc *rproc = (struct rproc *)p;
  91         struct da8xx_rproc *drproc = (struct da8xx_rproc *)rproc->priv;
  92         u32 chipsig;
  93
  94         chipsig = readl(drproc->chipsig);
  95         if (chipsig & SYSCFG_CHIPSIG0) {
  96                 /* Clear interrupt level source */
  97                 writel(SYSCFG_CHIPSIG0, drproc->chipsig + 4);
  98
  99                 /*
 100                  * ACK intr to AINTC.
 101                  *
 102                  * It has already been ack'ed by the kernel before calling
 103                  * this function, but since the ARM<->DSP interrupts in the
 104                  * CHIPSIG register are "level" instead of "pulse" variety,
 105                  * we need to ack it after taking down the level else we'll
 106                  * be called again immediately after returning.
 107                  */
 108                 drproc->ack_fxn(drproc->irq_data);
 109
 110                 return IRQ_WAKE_THREAD;
 111         }
 112
 113         return IRQ_HANDLED;
 114 }
 115
 116 static int da8xx_rproc_start(struct rproc *rproc)
 117 {
 118         struct device *dev = rproc->dev.parent;
 119         struct da8xx_rproc *drproc = (struct da8xx_rproc *)rproc->priv;
 120         struct clk *dsp_clk = drproc->dsp_clk;
 121
 122         /* hw requires the start (boot) address be on 1KB boundary */
 123         if (rproc->bootaddr & 0x3ff) {
 124                 dev_err(dev, "invalid boot address: must be aligned to 1KB\n");
 125
 126                 return -EINVAL;
 127         }
 128
 129         writel(rproc->bootaddr, drproc->bootreg);
 130
 131         clk_enable(dsp_clk);
 132         davinci_clk_reset_deassert(dsp_clk);
 133
 134         return 0;
 135 }
 136
 137 static int da8xx_rproc_stop(struct rproc *rproc)
 138 {
 139         struct da8xx_rproc *drproc = rproc->priv;
 140
 141         clk_disable(drproc->dsp_clk);
 142
 143         return 0;
 144 }
 145
 146 /* kick a virtqueue */
 147 static void da8xx_rproc_kick(struct rproc *rproc, int vqid)
 148 {
 149         struct da8xx_rproc *drproc = (struct da8xx_rproc *)rproc->priv;
 150
 151         /* Interupt remote proc */
 152         writel(SYSCFG_CHIPSIG2, drproc->chipsig);
 153 }
 154
 155 static struct rproc_ops da8xx_rproc_ops = {
 156         .start = da8xx_rproc_start,
 157         .stop = da8xx_rproc_stop,
 158         .kick = da8xx_rproc_kick,
 159 };
 160
 161 static int reset_assert(struct device *dev)
 162 {
 163         struct clk *dsp_clk;
 164
 165         dsp_clk = clk_get(dev, NULL);
 166         if (IS_ERR(dsp_clk)) {
 167                 dev_err(dev, "clk_get error: %ld\n", PTR_ERR(dsp_clk));
 168                 return PTR_ERR(dsp_clk);
 169         }
 170
 171         davinci_clk_reset_assert(dsp_clk);
 172         clk_put(dsp_clk);
 173
 174         return 0;
 175 }
 176
 177 static int da8xx_rproc_probe(struct platform_device *pdev)
 178 {
 179         struct device *dev = &pdev->dev;
 180         struct da8xx_rproc *drproc;
 181         struct rproc *rproc;
 182         struct irq_data *irq_data;
 183         struct resource *bootreg_res;
 184         struct resource *chipsig_res;
 185         struct clk *dsp_clk;
 186         void __iomem *chipsig;
 187         void __iomem *bootreg;
 188         int irq;
 189         int ret;
 190
 191         irq = platform_get_irq(pdev, 0);
 192         if (irq < 0) {
 193                 dev_err(dev, "platform_get_irq(pdev, 0) error: %d\n", irq);
 194                 return irq;
 195         }
 196
 197         irq_data = irq_get_irq_data(irq);
 198         if (!irq_data) {
 199                 dev_err(dev, "irq_get_irq_data(%d): NULL\n", irq);
 200                 return -EINVAL;
 201         }
 202
 203         bootreg_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 204         bootreg = devm_ioremap_resource(dev, bootreg_res);
 205         if (IS_ERR(bootreg))
 206                 return PTR_ERR(bootreg);
 207
 208         chipsig_res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 209         chipsig = devm_ioremap_resource(dev, chipsig_res);
 210         if (IS_ERR(chipsig))
 211                 return PTR_ERR(chipsig);
 212
 213         dsp_clk = devm_clk_get(dev, NULL);
 214         if (IS_ERR(dsp_clk)) {
 215                 dev_err(dev, "clk_get error: %ld\n", PTR_ERR(dsp_clk));
 216
 217                 return PTR_ERR(dsp_clk);
 218         }
 219
 220         rproc = rproc_alloc(dev, "dsp", &da8xx_rproc_ops, da8xx_fw_name,
 221                 sizeof(*drproc));
 222         if (!rproc)
 223                 return -ENOMEM;
 224
 225         drproc = rproc->priv;
 226         drproc->rproc = rproc;
 227         rproc->has_iommu = false;
 228
 229         platform_set_drvdata(pdev, rproc);
 230
 231         /* everything the ISR needs is now setup, so hook it up */
 232         ret = devm_request_threaded_irq(dev, irq, da8xx_rproc_callback,
 233                                         handle_event, 0, "da8xx-remoteproc",
 234                                         rproc);
 235         if (ret) {
 236                 dev_err(dev, "devm_request_threaded_irq error: %d\n", ret);
 237                 goto free_rproc;
 238         }
 239
 240         /*
 241          * rproc_add() can end up enabling the DSP's clk with the DSP
 242          * *not* in reset, but da8xx_rproc_start() needs the DSP to be
 243          * held in reset at the time it is called.
 244          */
 245         ret = reset_assert(dev);
 246         if (ret)
 247                 goto free_rproc;
 248
 249         drproc->chipsig = chipsig;
 250         drproc->bootreg = bootreg;
 251         drproc->ack_fxn = irq_data->chip->irq_ack;
 252         drproc->irq_data = irq_data;
 253         drproc->irq = irq;
 254         drproc->dsp_clk = dsp_clk;
 255
 256         ret = rproc_add(rproc);
 257         if (ret) {
 258                 dev_err(dev, "rproc_add failed: %d\n", ret);
 259                 goto free_rproc;
 260         }
 261
 262         return 0;
 263
 264 free_rproc:
 265         rproc_put(rproc);
 266
 267         return ret;
 268 }
 269
 270 static int da8xx_rproc_remove(struct platform_device *pdev)
 271 {
 272         struct device *dev = &pdev->dev;
 273         struct rproc *rproc = platform_get_drvdata(pdev);
 274         struct da8xx_rproc *drproc = (struct da8xx_rproc *)rproc->priv;
 275
 276         /*
 277          * It's important to place the DSP in reset before going away,
 278          * since a subsequent insmod of this module may enable the DSP's
 279          * clock before its program/boot-address has been loaded and
 280          * before this module's probe has had a chance to reset the DSP.
 281          * Without the reset, the DSP can lockup permanently when it
 282          * begins executing garbage.
 283          */
 284         reset_assert(dev);
 285
 286         /*
 287          * The devm subsystem might end up releasing things before
 288          * freeing the irq, thus allowing an interrupt to sneak in while
 289          * the device is being removed.  This should prevent that.
 290          */
 291         disable_irq(drproc->irq);
 292
 293         rproc_del(rproc);
 294         rproc_put(rproc);
 295
 296         return 0;
 297 }
 298
 299 static struct platform_driver da8xx_rproc_driver = {
 300         .probe = da8xx_rproc_probe,
 301         .remove = da8xx_rproc_remove,
 302         .driver = {
 303                 .name = "davinci-rproc",
 304         },
 305 };
 306
 307 module_platform_driver(da8xx_rproc_driver);
 308
 309 MODULE_LICENSE("GPL v2");
 310 MODULE_DESCRIPTION("DA8XX Remote Processor control driver");